MicroRNAs (miRNAs) are small noncoding RNA molecules that negatively regulate gene expression at the post-transcriptional level. Currently, there are 939 mature human miRNA sequences listed in the Sanger updated miRNA registry. There are approximately 1500 predicted miRNAs in the human genome that may regulate the expression of one third of our genes. By controlling the accumulation of the target protein(s) in cells, these regulatory RNA molecules participate in key functions in many physiological networks and their deregulation has been implicated in the pathogenesis of serious human disorders, such as cancer and infection. The implication of miRNAs in immune-mediated disorders such as rheumatoid arthritis (RA) has recently emerged suggesting that miRNA-based therapeutic approaches may have a promising potential in these diseases. Here, we provide an overview of the state-of-the-art on miRNAs in RA, focusing on both systemic and local features of the pathology.
